In order to increase the performance of an integrated circuit (IC), the voltage is often raised. However, if the voltage is raised, the higher stress causes the IC to age faster due to, for instance, hot carrier injection (HCI). Degradation of ICs, such as Complementary Metal Oxide Semiconductor (CMOS) chips, due to HCI is a common problem for most ICs. In general, HCI degradation is related to the frequency and the activity of an IC as well as the voltage. Every time a switch of the IC toggles HCI degradation occurs, as a result of the most HCI sensitive condition typically occurring when the device switches. Generally, the faster the rate of switching of the IC, the faster the IC ages.
To optimize performance and power of an IC, it is desirable to set the supply voltage to a point where the IC just satisfies the required performance. However, as the IC ages, the required voltage changes over time. Therefore, it is necessary to use conservative conditions in the designing of an IC, to account for the degradation caused by HCI. These conservative design conditions typically result in performance and power usage that is not optimized.